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Diameter Predicted UnitsSprint6220 Sprint ParkwayOverland ParkKS66251United Stateslylebe551144@gmail.comOperations and Management Area
Diameter Maintenance and Extensionsdiametercharging
This document specifies the conveyance of predicted usage
information for proper dimensioning of network services
that use Diameter based authorization.
When a User is authorized to use a service via Diameter
applications such as or , the Client is
not aware of the average load placed upon it by the User. This can
lead to overload situations or Diameter Clients being too conservative
and denying services to valid Users even whose presence would not
overload the service.
Given virtualization and the use of many software based services
the service capacity varies on a service instance, i.e. Diameter
Client, basis. Even though the Diameter Client is the same softawre
it will vary in terms of the load it can accept. Thus, a Diameter
Server cannot depend upon consistent capacities of a Diameter
Client.
This specification introduces the Predicted-Service-Units
Attribute Value Pair (AVP). This information conveys the
predicted usage introduced on the service by the authorized User.
Such information can be used by the Diameter Client to estimate
future load and proactively manage its resources.
Although this informaiton is conveyed from the Diameter Server to
the Client several system aspects are out of the scope of this
document:
How the Diameter Server acquired the information contained in the
Predicted-Service-Units AVP.
How the values in the Predicted-Service-Units AVP were determined.
The accuracy or validity of the values in the
Predicted-Service-Units AVP.
Specific actions the Diameter Client should take when its service
functions are overloaded or are predicted to be overloaded based
upon the information provided by Predicted-Service-Units.
Specific actions the Diameter Client takes to bring itself in/out
of service for new or existing Users.
When the value(s) or multiple types of Costs are provided they are
represented by the Time-Of-Day-Condition AVP defined in
and contained in a Predicted-Service-Units-Series AVP. This AVP
contains one or more Predicted-Service-Units. Multiple Cost types,
e.g. CC-Total-Octets and CC-Time, may be represented in the same
Predicted-Service-Units entry and in the same Predicted-Service-Units-Series
so long as no overlapping times exist for the same Cost Type.
In this document, the key words "MAY", "MUST", "MUST NOT", "OPTIONAL",
"RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be interpreted as
described in .
The Predicted-Service-Units AVP (AVP Code TBD1) is of type Grouped and
contains the amount of units that the Diameter Client
can expect to provide to the end user until the service must be
released or the new service authorizatoin request, e.g. Credit-Control-Request,
must be sent if a Granted-Service-Unit AVP has been applied
to the user's service. A client is not required to implement all
of the unit types, and it MUST ignore unknown or unsupported unit
types.
The Predicted-Service-Units AVP is defined as follows (per the grouped-
avp-def of ):
[ CC-Time ]
[ CC-Money ]
[ CC-Total-Octets ]
[ CC-Input-Octets ]
[ CC-Output-Octets ]
[ CC-Service-Specific-Units ]
[ Time-Of-Day-Condition ]
*[ AVP ]
]]>
The Time-Of-Day-Condition AVP is defined in , all other AVPs
are defined in .
The presence of this information is provided as anticipated load
information to the Diameter Client and is not intended to be
prescriptive in any manner regarding the user's service.
When the Time-Of-Day-Condition AVP is not present, the value(s) are assumed
to apply for the duration of the authorized session until this value is
updated as part of the Diameter application, e.g. a Diameter
Re-Auth-Request/Answer (RAR/RAA) message .
The Predicted-Service-Units-Series AVP (AVP Code TBD2) is of type
Grouped, and contains one or more Predicted-Service-Units
with non-overlapping times for each specific Cost type.
A client is not required to implement all
of the unit types, and it MUST ingore unknown or unsupported unit
types.
It is defined as follows (per the grouped-avp-def of [RFC6733]):
1*{ Predicted-Service-Units }
]]>
For each specific type of Cost, e.g. CC-Time, any two Predicted-Service-Units
values in the series MUST NOT contain overlapping time windows specified in their
Time-Of-Day-Condition values. When an entry has no Time-Of-Day-Condition present it
is assumed to apply at all times.
When Predicted-Service-Units are returned as part of an
authorization per or , the client MAY use
this information as guidance on projected load the new
user will generate on the service.
If the client supports/understnds the information provided in the
Predicted-Service-Units AVP, it can update its projected load.
Based upon this information it MAY take one or more of the
following actions (this is not exhaustive):
Redirect any new service requests at the service / protocol level.
Begin enforcing mechanisms to reduce the amount of service load
on a subset of services already established.
Remove itself from any system that directs new service requests
to it.
Initiate administrative functions to increase its capacity or
start the process of creating new intances to service future requests.
IANA allocated AVP codes in the IANA-controlled namespace registry
specified in Section 11.1.1 of for the following AVPs that
are defined in this document.
AVPAVP CodeSection DefinedData TypePredicted-Service-UnitsTBD1GROUPEDPredicted-Service-Units-SeriesTBD2GROUPED
The Diameter base protocol requires that each Diameter
implementation use underlying security; i.e., TLS/TCP, DTLS/SCTP or IPsec. These
mechanisms are believed to provide sufficient protection under the
normal Internet threat model; that is, assuming that the authorized
nodes engaging in the protocol have not been compromised, but that
the attacker has complete control over the communication channels
between them. This includes eavesdropping, message modification,
insertion, and man-in-the-middle and replay attacks. Note also that
this application includes a mechanism for application layer replay
protection by means of the Session-Id from . In these environments, the
use of TLS/TCP, DTLS/SCTP or IPsec is sufficient. The details of TLS/TCP, DTLS/SCTP or IPsec
related security considerations are discussed in the .
Because this application conveys past usage information (directly or
indirectly), it increases the interest for various security attacks.
Therefore, all parties communicating with each other MUST be
authenticated, including, for instance, TLS client-side
authentication. In addition, authorization of the client SHOULD be
emphasized; e.g., that the client is allowed to perform credit-
control for a certain user. The specific means of authorization are
outside of the scope of this specification but can be, for instance,
manual configuration.
The attributes provided by this solution MUST be assumed to be
privacy sensitive by both the client and server.
&RFC2119;
&RFC4006;
&RFC5777;
&RFC6733;
&RFC7155;